Textiles: fiber preparation – Assembling – Web forming
Reexamination Certificate
2001-02-16
2001-12-18
Calvert, John J. (Department: 3765)
Textiles: fiber preparation
Assembling
Web forming
C019S301000, C403S294000, C425S080100
Reexamination Certificate
active
06330735
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to apparatus and method for forming an airlaid fibrous article. The fibrous article can be a fibrous web which can be employed to produce an absorbent pad for applications such as disposable diapers, child's training pants, feminine care articles, incontinence articles, and the like.
BACKGROUND OF THE INVENTION
In the general practice of forming fibrous web materials, such as laid fibrous articles, it has been common to utilize a fibrous sheet of cellulosic or other suitable absorbent material which has been fiberized in a conventional fiberizer, or other shredding or comminuting device, to form discrete fibers. In addition, particles of superabsorbent material have been mixed with the fibers. The fibers and superabsorbent particles have then been entrained in an air stream and directed to a foraminous forming surface upon which the fibers and superabsorbent particles have been deposited to form an absorbent fibrous web.
The forming surfaces utilized in such systems have been constructed with a wire or screen grid and can typically employ a pneumatic flow mechanism, such as vacuum suction apparatus, to define a differential pressure zone on the forming surface and impose a pressure differential thereon. The pressure difference has typically provided an airflow through the openings or perforations in the screen or grid of the forming surface. The use of vacuum suction to draw the air-entrained fiber stream onto the forming surfae, and pass the airflow through the forming surface has been employed in high-speed commercial operations.
The prior practice of forming airlaid fibrous webs has also employed various mechanisms to produce gradations in basis weight along the fibrous webs. For example, the mechanisms have been employed produce gradations of basis weight along a longitudinal direction of the formed web, i.e., in the direction of movement of the fibrous web through the forming process. Conventional mechanisms have also been employed for providing basis weight variations along a transverse, cross-direction of the formed web.
Conventional vacuum-deposition systems, such as those described above, have continued to exhibit various shortcomings. For example, with the conventional devices, it has been difficult to maintain a well mixed, superabsorbent distribution in narrow regions of the fibrous web. The conventional systems can excessively funnel the superabsorbent particles toward the cross-directional center of the forming surface. The conventional techniques have also produced an excessively non-uniform distribution of basis weight of fibrous material along the cross-direction in the narrow regions of the fibrous web. Additionally, the conventional techniques have not provided a sufficiently convenient method or apparatus for changing the dimensions of the formed fibrous web. Where the formed fibrous web includes an interconnected plurality of web segments, it has been difficult to adjust the dimensions of the desired web segments without a significant reconstruction of the forming surface. Changes to the dimensions of the formed fibrous web have required the procurement, storage and maintenance of multiple sets of forming screens and introduced excessive downtime and change over costs. Accordingly, it would be a substantial advance in the art to provide a method and apparatus which can provide a more efficient removal of the formed web from the forming surface, and can better provide an adjusting of the dimensions of the intended web segments to more efficiently form components for articles of various, different sizes.
BRIEF DESCRIPTION OF THE INVENTION
The present invention provides a distinctive method and apparatus for forming an airlaid fibrous article. An apparatus for forming an airlaid fibrous web on a moving surface has a longitudinal direction, a lateral cross-direction, and a depth-wise, z-direction. The apparatus can include a contoured foraminous member having a first side portion, a laterally opposed second side portion, and a depth contour formed into a thickness of the foraminous member. A longitudinally extending, first side-masking member can be located superjacent the first side portion of the foraminous member, and can have a first inboard side wall surface. In a particular feature, the first side-masking member can be at least laterally movable relative to the foraminous member. At least a second, separately provided, longitudinally extending, side-masking member can be located superjacent the second side portion of the foraminous member, and can have a second inboard side wall surface. In a particular aspect, the second side-masking member can be at least laterally movable relative to the foraminous member. In another feature, a first releasable attachment system can selectively hold at least the first side-masking member at a substantially fixed position relative to the foraminous member during a movement of the foraminous member along the longitudinal direction.
In a process or method aspect, the invention can include a moving of a selected surface, and a providing of a foraminous member. The foraminous member can be provided with a first side portion, a laterally opposed second side portion, and a depth contour formed into a thickness of the foraminous member. A longitudinally extending, first side-masking member can be located superjacent the first side portion of the foraminous member, and can be provided with a first inboard side wall surface. In a particular feature, the first side-masking member can be configured to be at least laterally movable relative to the foraminous member. At least a second, separately provided, longitudinally extending, side-masking member can be located superjacent the second side portion of the foraminous member, and can be provided with a second inboard side wall surface. In a particular aspect, the second side-masking member can be configured to be at least laterally movable relative to the foraminous member. Another feature can include a providing of a first releasable attachment system which can selectively hold at least the first side-masking member at a substantially fixed position relative to the foraminous member during a movement of the foraminous member along the longitudinal direction.
In its various aspects and features, the present invention can more effectively help to increase the quantity of absorbent material distributed into desired higher-basis-weight sections of the forming surface. Additionally, the technique of the invention can better provide a desired cross-directional distribution of superabsorbent material in the appointed high-basis-weight sections of the forming surface. The releasable attachment system employed with the present invention can improve the ability to adjust the method and apparatus to accommodate the formation of fibrous webs with different dimensions, particularly different cross-directional dimensions. The various features and aspects of the invention can also help reduce the fabrication costs of the forming surface and can help facilitate the cleaning and maintenance of the forming surface.
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Berken Bradley John
Datta Paul Joseph
Hahn John Timothy
St. Louis Raymond Gerard
Venturino Michael Barth
Calvert John J.
Kimberly--Clark Worldwide, Inc.
Welch Gary L.
Yee Paul
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